This invention concerns a system of hand-held multiple laser emitters suitable for directing an infrared measurement device onto a target surface.
The invention relates to devices for non-contact temperature measurement which include a detector upon which electromagnetic radiation emanating from a surface measurement spot or energy zone is imaged by known imaging optics, in combination with a laser directed sighting device. The sighting device marks the position and/or size of the measured spot by illumination from at least two laser beams or lines into a visible display pattern originating from separate lasers.
Non-contact infrared measurement devices comprise an infrared detector in combination with an optical system to focus the infrared radiation from the surface being measured onto the detector, together with a laser directed sighting system. In hand held devices it is important for the operator to be able to direct the device at the measurement point. A sighting display on the target surface of laser light formed of lines or dots will outline the measurement area, and/or indicate the center thereof and allow reliable measurement of the thermal energy zone being measured.
There is an upper limit on the power of each laser beam or sighting ray which may be used for sighting such a device. Working conditions such as long distance from the device to the target or obscure atmosphere may require a brighter laser display than is available from a single emitter of limited brightness. The present invention provides at least two separate laser emitters working together to produce a brighter display than that from a single laser.
In an embodiment of the invention multiple laser emitters (2) are provided, and one or more of these emitters may illuminate a beam directing optical element (4), such as a beam splitter, a lens or prism, for example, a diffraction lens or grating and/or a refractive optical element, which directs an illuminating laser light marking display onto a target surface. Splitting a laser beam more than once as above produces more complex patterns of light. A laser line generator may be used with a laser diode to produce a line, vis a vis, a dot. Both lines and dots may comprise the marking display. Multiple lasers cooperating to produce a marking display of selectable brightness using intermediary directing optical elements.
In principle, long range far focusing of the measurement spot image onto the detector is distinguished from closing short range focusing. In the case of long range focusing, the detector is imaged at infinity and in the case of short range focusing it is imaged on a focus plane at a finite distance from the detector. Different related sighting systems are known for close and far focusing and visualization of the measured spot. Marking the outline of the measured spot and/or indicating the center of the measured area by a single laser are known methods of visualization.
In a preferred example of the best mode of carrying out the invention an array of multiple laser emitters and respective optical directing elements is mounted with an infrared detector and infrared optical system on a hand held support; and a plurality of individual lasers is linked, under control of the operator, with on/off and/or power control switching means (electrical, optical or mechanical). At a first switch position, power supply to the lasers is cut off to all or some lasers. At a second switch position, power supply to the lasers is cut off to all or some lasers. At a second switch position all or some of the lasers are powered on. One or more laser beams or sighting rays is preferably also directed at the center of the measurement area to produce a bright spot or central area (FIG. 1-4) to indicate the center of the field of view. When more than one beam strikes a selected location, e.g., the center, a much brighter spot is produced where the beams intersect. The location on the target surface where two or more beams intersect is enhanced in visibility according to the number of impinging beams or sighting rays. One or more laser beams may be further split, e.g. by diffraction, to produce a more complex light pattern or to outline the target and/or to indicate an edge of the detector field of view. For example, one laser beam may indicate the center of the measurement field and at least two further beams may indicate the edges and thereby disclose the calculable measurement area of the zone, which area may then appear on a display means together with temperature and distance measured by the device from laser to target surface.